1978 35 HP Johnson - repair or replace

[TerryMSU]

Hello:
I have a 1978 Johnson 35HP electric start standard shaft motor. It has two or possibly three issues.

1. Lower unit leaks. Probably as a minimum, the propeller shaft seal. It was leaking lower unit oil at the propeller. Will also do the water pump at the same time.
2. Won't crank consistently. Suspect that the brushes are shot.
3. May need carb rebuilt.

I am trying to decide whether to repair the motor or just replace it. I will almost certainly be replacing the boat hull as it has serious rot issues and is likely not worth fixing.

Should I dump the motor or try to fix it? I know that I need to check compression and if that is also bad, I will be dumping it. Spark appears to be good when I get it turning over at a decent speed.

Mostly I want a decent motor at a decent price. I had the same motor on a pontoon and it ran great. What is this guy worth (when running properly) and what should I expect to pay to get it running right?

I know I need to get the original manual. If I get that does it have good specific pictures and instructions? Am I going to need any special tools that I can't fabricate easily? How difficult are these repairs for a non-professional to do?

Thanks,
Terry

 

[tashasdaddy]

Re: 1978 35 HP Johnson - repair or replace

dump it i have an OB graveyard.

90% of starter problems are bad connections. remove and clean both ends of the battery cables, so that they are shiney, also the cable from the solenoid to starter. check for nicks in the cables. and make sure the connectors are on the wire good. the cable tend to corrode from the inside out, if nicked, corroded wires, and connections, heat up and cause resistance to the follow of electricity, thus the starter doesn't get enough. you can also take jumper cable pos battery post to large post on starter. with a good connection, the engine should spin. then if the starter is good clean everything and retest. then trouble shoot solenoid. starters can be rebuit at a starter/alternator shop, much cheaper than a new one.

also have the battery load tested at the auto parts store, free, i've had new batteries go bad


carb kits are easy.

read this, probably normal, always change the seal on the drain and vent plugs, # 1 place for intrusion. http://forums.iboats.com/showthread.php?t=207285

 

[samo_ott]

Re: 1978 35 HP Johnson - repair or replace

If it has good compression I'd keep it and fix it. The value of the engine changes in different areas and what folks are willing to pay for an older engine...

 

[jbjennings]

Re: 1978 35 HP Johnson - repair or replace

I wouldn't sell the motor....In my area a non-running motor isn't worth much, but it is worth something to you and will probably be as good as new with a little work. Since your boat is junk, you'll probably be more likely to find a whole rig with a motor for about the same price as a boat and trailer without a motor. You can always use your old one for backup once it's fixed. Of course this is true in my area but may not be in yours.
JMO--good luck,
JBJ

 

[samo_ott]

Re: 1978 35 HP Johnson - repair or replace

That was how I started. I always needed a backup! Then backups for the backups... 30 engines later I gotta build more storage space for em on the back 40!

 

[jbjennings]

Re: 1978 35 HP Johnson - repair or replace

That's true, Steve, 30 motors is just plain overkill. Now, me, I only have 6 or 7 "back-ups". A person only needs about 10, or 15, or 20...
BTW, I'm waiting on a '56 evin. 15hp for my next backup (100bucks)
JBJ

 

[TerryMSU]

Re: 1978 35 HP Johnson - repair or replace

bump

 

[HighTrim]

Re: 1978 35 HP Johnson - repair or replace

Did you check compression yet? resolve the cranking issue?